DIY ventilation heat exchanger

[Jim_UK]

Originally Posted by NiHaoMike

You could build a water source heat pump to supply some of the heat, with the generator supplying the rest. Should be far more efficient than idling the "APU" purely for heat. Also, when connected to mains (maybe not often enough for it to really matter), the APU wouldn't have to run at all.

Ok, I've done a couple of hours of googling & reading about water source heat pumps. An Open Loop Water Sourced Heat Pump is of great interest now.

Alas these seem to be aimed at moderate sized houses or larger. The smallest I did find was a Dimplex SIH 4 ME (4KW) but it is listing at £3.5K/$6K. Several times more than a 5KW Diesel Water Heater designed for a Marine environment. The power use of the heat pump will need looking into carefully.

Also I have a feeling from my initial reading it would take 1KW.hr as an input (EG in a 4KW Heat Pump that needs 1KW electrickery), whereas a 5KW Diesel Water Heater would need 35-50 W.hr as an input (for the circulation pump & control unit aspects... IE nearly nothing). Power is a big concern as previously mentioned.

Still, DIY to the rescue? Do you have any more specific advice/pointers in this regard?

Cheers!